Although now that I look at it closer, the last time I had to identify
a tapped hole (actually a captive nut) it was a M12 fine thread, so
that still wouldn't have helped... I guess nobody makes one tool to
rule them all, although that is pretty darn close. I just determined
what that one was by process of elimination; I tried a 1/2" NC, 1/2"
NF, and M12 standard pitch, none of them worked and it looked finer
than M12 standard so I brilliantly deduced what it must be :) (I also
took the part - a spare tire carrier - to the auto parts store with me
just to be sure... It is sad when your FLAPS has a better selection
of hardware than your local hardware store, but c'est la vie.)
nate